大麦根质膜微囊的制备及其H^+,Ca^(2+)转运活性

Preparation of Sealed Plasma Membrane Vesicles from Barley Roots and Their Activities in H^+ and Ca^(2+) Transport

用蔗糖密度梯度离心法制备出密闭程度较高的大麦根细胞质膜微囊。喹吖咽荧光猝灭和^(45)Ca^(2+)同位素示踪测定表明所制备的微囊具H^+,Ca^(2+)转运活性。对制备出的质膜制剂纯度和膜朝向进行了分析,并探讨了质膜纯化中影响膜微囊密闭性的因素。匀浆液和悬浮液巾的单价离子盐有利于密闭膜微囊的形成。蔗糖密度梯度和葡聚糖密度睇度离心法均可得到密闭性较高的膜微囊,但后者的纯化效果较差。

Sealed plasma membrane (PM) vesicles were obtained from barley roots by sucrose gradient centrifugation. The purity of plasma membrane preparation was investigated and the sidedness of PM vesicles was estimated. They possessed H^+- and Ca^(2+)-transport activities detected by quinacrine fluoresence probe and filtration method with ^(45) Ca^(2+) as a tracer, respectively. The factors that influenced the tightness of the sealing of PM vesicles were studied. Grinding with the medium containing KI before differential centrifugation and incubation with suspending medium containg KCl in ice for 15 minutes before sucrose density gradient centrifugation favored the formation of sealed PM vesicles. Sealed membrane vesicles could be prepared by dextran density gradient centrifugation, but hte purity was lower than that by sucrose density gradient centrifugation. The causes of the above results were discussed.